Dynamic calibration of optical properties of a dimming element

ABSTRACT

An imager assembly including calibration functionality and a housing. An imager is disposed inside the housing. The imager includes a lens assembly. An electro-optic element is disposed on a wall of the housing and operable between a substantially clear condition and a substantially darkened condition. A light source directs light at the electro-optic element which redirects the light toward the lens assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit under 35 U.S.C. §120 to U.S. patent application Ser. No. 16/018,263, filed on Jun. 26,2018, entitled “DYNAMIC CALIBRATION OF OPTICAL PROPERTIES OF A DIMMINGELEMENT,” which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/524,963, filed on Jun. 26, 2017, entitled“DYNAMIC CALIBRATION OF OPTICAL PROPERTIES OF A DIMMING ELEMENT,” thedisclosures of which are hereby incorporated herein by reference intheir entirety.

TECHNOLOGICAL FIELD

The present invention generally relates to imager assemblies andutilizing dynamic calibration assemblies to adjust optical properties ofcaptured images.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, an imager assembly comprises ahousing and an imager disposed inside the housing. The imager includes alens assembly. An electro-optic element is disposed on a wall of thehousing and is operable between a substantially clear condition and asubstantially darkened condition. A light source directs light at theelectro-optic element which redirects the light toward the lensassembly.

In another aspect of the present disclosure, a method of calibrating animager assembly comprises positioning an imager to take images throughan electro-optic element. The imager is synchronized with a light sourcesuch that every Nth frame is used as a calibration frame. The lightsource is activated during the calibration frame. An image is storedduring activation of the light source and properties are compared with abaseline profile to determine color and intensity shift of theelectro-optic element.

In yet another aspect of the present disclosure, a method of calibratingan imager assembly comprises positioning an imager to take imagesthrough an electro-optic element. The imager is aligned with theelectro-optic element such that a dimming region and a calibrationregion are defined within a field of view of the imager. A color andintensity shift of the image is compared at the calibration region witha color and intensity shift of the image taken through the electro-opticelement.

In yet another aspect of the present disclosure, an imager assemblycomprises a housing and a primary imager disposed inside the housing.The primary imager includes a lens assembly. An electro-optic element isdisposed adjacent to the lens assembly within the housing and isoperable between a substantially clear condition and a substantiallydarkened condition. A calibration imager is disposed within the housingand is configured to collect image data from a calibration light source,wherein a portion of the electro-optic element is disposed between thecalibration imager and the calibration light source.

In yet another aspect of the present invention, a method of calibratingan imager assembly comprises positioning a primary imager to take imagesthrough an electro-optic element. A calibration imager is positioned totake images of image data provided by a calibration light source throughan electro-optic element. Properties of the image are compared with abaseline profile to determine color and intensity shift of theelectro-optic element.

These and other features, advantages, and objects of the presentinvention will be further understood and appreciated by those skilled inthe art by reference to the following specification, claims, andappended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top perspective view of a vehicle with an imager assemblyinstalled inside a housing of a roof mounted antenna of the presentdisclosure;

FIG. 1A is a front top perspective view of the roof mounted antenna andimager assembly of FIG. 1;

FIG. 2 is a schematic view of an imager assembly of the presentdisclosure;

FIG. 3 is a schematic view of another imager assembly of the presentdisclosure;

FIG. 4 is a schematic view of a calibration region and dimming region ofan imager assembly of the present disclosure;

FIG. 5 is a rear top perspective view of a roof mounted antenna andimager assembly of the present disclosure;

FIG. 6 is a front schematic view of an imager assembly of the presentdisclosure;

FIG. 7 is a side cross-sectional elevational view of an imager of thepresent disclosure;

FIG. 8 is a schematic view of another imager assembly of the presentdisclosure;

FIG. 9 is an exemplary image of optical properties of baseline imagedata;

FIG. 10 is an exemplary image of image data collected through a dimmedelectro-optic; and

FIG. 11 is an exemplary image of image data collected through a dimmedelectro-optic after the electro-optic has been compensated for color andintensity shift.

DETAILED DESCRIPTION

The present illustrated embodiments reside primarily in combinations ofmethod steps and apparatus components of the imager assembly. Theapparatus components and method steps have been represented, whereappropriate, by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present disclosure so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein. Further, like numerals inthe description and drawings represent like elements.

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the invention as oriented in FIG. 1. Unlessstated otherwise, the term “front” shall refer to the surface of thedevice closer to an intended viewer of the device, and the term “rear”shall refer to the surface of the device further from the intendedviewer of the device. However, it is to be understood that the inventionmay assume various alternative orientations, except where expresslyspecified to the contrary. It is also to be understood that the specificdevices and processes illustrated in the attached drawings, anddescribed in the following specification are simply exemplaryembodiments of the inventive concepts defined in the appended claims.Hence, specific dimensions and other physical characteristics relatingto the embodiments disclosed herein are not to be considered aslimiting, unless the claims expressly state otherwise.

The terms “including,” “comprises,” “comprising,” or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus. An element proceeded by “comprises a . . . ” does not,without more constraints, preclude the existence of additional identicalelements in the process, method, article, or apparatus that comprisesthe element.

Referring to FIGS. 1-2, the reference numeral 10 generally designates animager assembly that includes a housing 12 and an imager 14 disposedinside the housing 12. The imager 14 includes a lens assembly 16. Anelectro-optic element 18 is disposed on a wall 20 of the housing 12 andis operable between a generally clear condition and a generally darkenedcondition. A light source 22 directs light 23 at the electro-opticelement 18, and the electro-optic element 18 redirects the light towardthe lens assembly 16.

The housing 12 may be constructed from a variety of materials includingmetals and plastics, and may be disposed inside or outside of a vehicle24. As illustrated, the imager assembly constructions set forth hereinmay be disposed in a satellite antenna housing, behind a vehicle bodypanel, etc., and are not limited to the specific configurationsillustrated herein. Although the imager assembly 10 includes a field ofview 26 that is directed rearwardly, the field of view 26 could extendin any direction relative to the vehicle. In the illustrated embodiment,the wall 20 of the housing 12 includes an at least partiallytransmissive and partially reflective portion, which in the illustratedembodiment includes the electro-optic element 18. The electro-opticelement 18 includes first and second substrates 34, 36. The firstsubstrate 34 defines a first surface 38 and a second surface 40. Thesecond substrate 36 defines a third surface 42 and a fourth surface 44.An electro-optic medium 46 is disposed between the first substrate 34,the second substrate 36, and seals 48 are disposed about the dimmingelement. The third surface 42 and/or the fourth surface 44 may include atransflective coating to allow external light to pass into the housing12, but reflect internal light from the light source 22. However, insome instances, the transflective coating may be on the first surface 38or second surface 40.

With reference again to FIG. 2, the light source 22 is disposed belowthe imager 14 and the lens assembly 16. However, it will be understoodthat the light source 22 may be disposed at other areas within thehousing 12. Regardless, the light source 22 is generally configured todirect the light 23 at the electro-optic element 18, which redirects thelight toward the lens assembly 16. The imager assembly 10 is generallyconfigured such that the imager 14 is synchronized with the light source22, such that every Nth frame taken by the imager 14 is used as acalibration frame by a controller 50 and is not displayed to the user.The light source 22 is pulsed on during the calibration frame and imagedata is captured by the imager 14. The controller 50 then compares acolor of the image to a baseline image profile to determine if there hasbeen any color or intensity shift of the electro-optic element 18. Analgorithm configured to compensate for color and intensity shift runswithin a processor of the controller 50 that is in electricalcommunication with the imager 14. The processor subsequently modifiesthe image data before being displayed to a user on a display module 52.The display module may be positioned anywhere including inside thevehicle 24 at a rearview device 54 or dash 56, or outside of the vehicle24.

With reference again to FIGS. 1-2, it will be understood that the Nthframe may be as frequent as every other frame taken by the imager 14,but could also be as infrequent as every 30 seconds a frame is used forcalibration. In addition, it is also contemplated that the sampling ratecould be based on the voltage differential measured at the electro-opticelement 18. As the voltage differential increases, the sampling rate mayincrease as the electro-optic element 18 may be darkening or becomingmore clear. In addition, it is generally contemplated that the samplingrate may be based on the time of day (dusk and dawn), the time of year,or the state of use of the vehicle (whether the vehicle is in drive,reverse, park, etc.).

A method of using calibration functionality of the imager assembly 10includes positioning the imager 14 to take images through theelectro-optic element 18. The imager 14 is then synchronized with thelight source 22, such that every Nth frame is used as a calibrationframe. The light source 22 is activated during each calibration frame.Image data is captured by the imager 14 and stored in memory duringactivation of the light source 22, and properties of the image arecompared with a baseline image profile to determine color and intensityshift of the electro-optic element 18. As noted above, a transflectivecoating may be applied to one of the first, second, third, and fourthsurfaces 38, 40, 42, 44 of the first and second substrates 34, 36 of theelectro-optic element 18 to allow external light to pass into thehousing 12, but reflect internal light that is provided by the lightsource 22. In addition, it is also contemplated that a reflectivepolarizer may be positioned adjacent to the electro-optic element 18 toallow light to pass into the housing 12, but minimize light from leavingthe housing 12.

With reference now to FIGS. 3-7, in an alternate construction, an imagerassembly 100 is illustrated that includes another manner of calibration.This configuration uses many of the same features as the previouslydescribed construction. It will be understood that like features includelike references numerals across the various embodiments set forth inthis disclosure. The imager assembly 100 also includes a lens assembly101 and an electro-optic element 102. The electro-optic element 102includes a calibration region 104, and a dimming region 106 separated bya seal 107. The electro-optic medium 46 at the dimming region 106 and atthe calibration region 104 may be constructed from the same or differentmaterials. It is contemplated that the seal 107 may be generally clearin some applications. The calibration region 104 does not dim and isgenerally clear. In this instance, an imager 108 is positioned tocapture image data through an electro-optic element 102. Theelectro-optic element 102 may be positioned inside the housing 12 (FIG.7) or may be positioned at an opening defined by the housing 12 (FIG.3). Regardless, the imager 108 is aligned with the electro-optic element102, such that the dimming region 106 and the calibration region 104define an area 110 that is aligned with the field of view 26 of theimager 108. The calibration region 104 will likely be a small portion ofthe overall area 110 of the electro-optic element 102. Depending on theapplication, the calibration region 104 may be on a top, bottom, or sideof the electro-optic element 102. In addition, the calibration region104 may be positioned such that the calibration region 104 will not bevisible on the display module 52 disposed within the vehicle 24 thatprovides image data to the user. The controller 112 compares a color andintensity shift of the image at the calibration region with a color andintensity shift of the image taken at the dimming region 106 of theelectro-optic element 102. The controller 112 may be positioned on acircuit board 114. An algorithm is subsequently activated to modify theimage based on the comparison of the calibration region 104 with thedimming region 106. The modified image is then displayed on the displaymodule 52 to a user.

With reference again to FIGS. 3-7, it will be understood that color andintensity shift properties of the dimming region 106 and the calibrationregion 104 may be stored in non-volatile memory of the imager 108. Thisdata may be recalled by the controller 112 that evaluates the color andintensity shift of the dimming region 106 and the calibration region 104at a later time. The seal 107 may be disposed between the calibrationregion 104 and the dimming region 106. In addition, a dead zone area 120may be identified between the calibration region 104 and the dimmingregion 106. Image data that is captured at the dead zone area 120 may bediscarded by the controller 112 and not utilized in evaluating any coloror intensity shift. In addition, the controller 112 in this constructionmay include real-time content aware identification of the suitability ofpixels for use in calibration. Stated differently, the controller 112may run an algorithm that measures for similarities and/or differencesin the calibration and dimming regions 104, 106 and these similaritiesand differences may be used for calibration of the dimming region 106.

With reference now to FIG. 8, yet another configuration set forth inthis disclosure includes an imager assembly 200 with calibrationfunctionality. The imager assembly 200 includes a housing 202, and aprimary imager 204 disposed within the housing 202. The primary imager204 includes a lens assembly 206 and an electro-optic element 208 thatis disposed adjacent to the lens assembly 206. The electro-optic element208 may include a structure similar to that of the electro-optic element18 disclosed above and illustrated in FIG. 2. The electro-optic element208 and the lens assembly 206 are disposed within the housing 202 behinda cover glass 209. The electro-optic element 208 includes featuressimilar to those set forth in relation to the electro-optic element 18.The lens assembly 206 is disposed between the primary imager 204 and theelectro-optic element 208. The electro-optic element 208 is operablebetween a generally clear condition and a generally darkened or dimcondition. A calibration imager 210 is also disposed within the housing202 and is configured to collect image data from a calibration lightsource 212. A portion of the electro-optic element 208 is disposedbetween the calibration imager 210 and the calibration light source 212.In this instance, a periodic or continual calibration of the image dataoccurs based on image data collected by the calibration imager 210.While the user is able to see image data collected by the primary imager204 through the electro-optic element 208, the image data is modifiedbased on an algorithm that functions to modify the image before beingdisplayed to a user based on image data collected by the calibrationimager 210. For example, in the event the primary imager 204 is beingused in very bright, ambient conditions, the electro-optic element 208will dim. As the electro-optic element 208 dims, the calibration lightsource 212 directs light through the electro-optic element 208 at thecalibration imager 210. If the color and intensity of the electro-opticelement 208 shifts as noted by the calibration imager 210, modificationscan be made by the image data collected by the primary imager 204 beforebeing displayed to the user.

With reference again to FIG. 8, the lens assembly 206 is shown betweenthe primary imager 204 and the electro-optic element 208. However, theelectro-optic element 208 could also be positioned between the primaryimager 204 and the lens assembly 206. This construction for the imagerassembly 200 would work similarly to the illustration of FIG. 8, butimage data would be adjusted based on light first passing through thelens assembly 206, then the electro-optic element 208 before beingcaptured by the primary imager 204.

One method of calibrating the imager assembly 201 using the imagerassembly 200 includes positioning the primary imager 204 to take imagesthrough the electro-optic element 208. The calibration imager 210 alsotakes images of image data that is provided by the calibration lightsource 212 through the electro-optic element 208. Properties of theimage data are then compared with a baseline image profile to determinecolor and intensity shift of the electro-optic element 208. Thecalibration functionality of the imager assembly 200 may utilize aseparate calibration region 220 (between the calibration imager 210 andthe calibration light source 212) on the electro-optic element 208 toprovide a reference for correction. The calibration region 220 isanalyzed by a separate imaging device (the calibration imager 210)altogether. An optical isolator 222 extends across the housing 202 andis interrupted by the electro-optic element 208. The optical isolator222 is configured to isolate the primary imager 204, the lens assembly206, and a primary portion of the electro-optic element 208 from opticaloverlap with the calibration imager 210 and the calibration light source212. The purpose of the optical isolation is to prevent light from thecalibration light source 212 from reaching the primary imager 204 andalso to prevent external light from reaching the calibration imager 210.

With reference now to FIGS. 9-11, an example of corrected images can beobserved. Specifically, a baseline image is shown in FIG. 9. After theelectro-optic element is dimmed, a color and intensity shift occurs as aresult of the image data being collected through the electro-opticelement (FIG. 10). After compensation, which is governed by an algorithmwithin a processor of the controller disposed within the imager assemblyor elsewhere within the system, the image can be displayed to the user(FIG. 11).

The color correction applied in these techniques is configured to allowthe presence of a dimming element as part of an imager stack-up withoutnegatively affecting image quality. One application of this technique isto allow the dimming element to act as a gain factor in the imagingdevice to allow more flexibility and exposure control settings.Consequently, this can be used to improve dynamic range capabilities andallow for greater ability to mitigate the effect of time varying lightsources on the imager.

It will be understood by one having ordinary skill in the art thatconstruction of the described invention and other components is notlimited to any specific material. Other exemplary embodiments of theinvention disclosed herein may be formed from a wide variety ofmaterials, unless described otherwise herein.

For purposes of this disclosure, the term “coupled” (in all of itsforms, couple, coupling, coupled, etc.) generally means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents. Such joining may be permanent in nature or may be removableor releasable in nature unless otherwise stated.

It is also important to note that the construction and arrangement ofthe elements of the invention as shown in the exemplary embodiments isillustrative only. Although only a few embodiments of the presentinnovations have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements shown as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or number of adjustmentpositions provided between the elements may be varied. It should benoted that the elements and/or assemblies of the system may beconstructed from any of a wide variety of materials that providesufficient strength or durability, in any of a wide variety of colors,textures, and combinations. Accordingly, all such modifications areintended to be included within the scope of the present innovations.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions, and arrangement of the desired andother exemplary embodiments without departing from the spirit of thepresent innovations.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present invention. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

It is also to be understood that variations and modifications can bemade on the aforementioned structures and methods without departing fromthe concepts of the present invention, and further it is to beunderstood that such concepts are intended to be covered by thefollowing claims unless these claims by their language expressly stateotherwise.

What is claimed is:
 1. An imager assembly comprising: a housing; aprimary imager disposed inside the housing, the primary imager includinga lens assembly; an electro-optic element disposed adjacent to the lensassembly within the housing and operable between a substantially clearcondition and a substantially darkened condition; and a calibrationimager disposed within the housing and configured to collect image datafrom a calibration light source.
 2. The imager assembly of claim 1,wherein a portion of the electro-optic element is disposed between thecalibration imager and the calibration light source.
 3. The imagerassembly of claim 1, wherein calibration of the image data occurs basedon image data collected by the calibration imager.
 4. The image assemblyof claim 3, wherein the calibration is done continuously.
 5. The imageassembly of claim 3, wherein the calibration is done periodically. 6.The imager assembly of claim 1, wherein image data from images capturedby the primary imager is modified based on an algorithm that functionsto modify the image data before the image is displayed to a user, themodifications based on image data collected by the calibration imager.7. The imager assembly of claim 1, wherein, when the primary imager isbeing used in bright conditions, the electro-optic element is configuredto dim.
 8. The imager assembly of claim 7, wherein, as the electro-opticelement dims, the calibration light source directs light through theelectro-optic element at the calibration imager.
 9. The imager assemblyof claim 1, wherein, upon the calibration imager detecting a shift incolor or intensity of the electro-optic element, the primary imager isconfigured to apply modifications to the image data collected by theprimary imager before the image data is displayed to a user.
 10. Theimager assembly of claim 1, wherein the lens assembly is disposedbetween the primary imager and the electro-optic element.
 11. The imagerassembly of claim 1, wherein the electro-optic element is disposedbetween the primary imager and the lens assembly.
 12. The imagerassembly of claim 11, wherein image data is adjusted based on lightfirst passing through the lens assembly, then through the electro-opticelement before being captured by the primary imager.
 13. A method ofcalibrating an imager assembly, comprising: providing an imager assemblycomprising: a housing; a primary imager disposed inside the housing, theprimary imager including a lens assembly; an electro-optic elementdisposed adjacent to the lens assembly within the housing and operablebetween a substantially clear condition and a substantially darkenedcondition; and a calibration imager disposed within the housing andconfigured to collect image data from a calibration light source;wherein a portion of the electro-optic element is disposed between thecalibration imager and the calibration light source; positioning theprimary imager to capture images through the electro-optic element;capturing images of image data that is provided by the calibration lightsource through the electro-optic element; and comparing properties ofthe image data with a baseline image profile to determine color andintensity shift of the electro-optic element.
 14. The method of claim13, further comprising utilizing a separate calibration region on theelectro-optic element to provide a reference for correction.
 15. Themethod of claim 14, wherein the separate calibration region is disposedbetween the calibration imager and the calibration light source.
 16. Themethod of claim 13, further comprising analyzing, by the calibrationimager, the calibration region.
 17. The method of claim 13, wherein anoptical isolator extends across the housing and is interrupted by theelectro-optic element.
 18. The method of claim 17, wherein the opticalisolator is configured to isolate the primary imager, the lens assembly,and a primary portion of the electro-optic element from optical overlapwith the calibration imager and the calibration light source.
 19. Themethod of claim 17, wherein the optical isolation prevents light fromthe calibration light source from reaching the primary imager and alsoprevents external light from reaching the calibration imager.